1. Field of the Invention
The invention relates to the printing art.
2. Brief Description of the Prior Art
The following prior art is made of record: PAXAR 7500 Operation/Maintenance and Parts List January 1995 and PAXAR 8500 Operation/Maintenance and Parts List November 1996.
The invention relates to an improved printer for printing on webs of labels.
It is a feature of the invention to provide an improved arrangement to facilitate threading a label web through a printer. The label web is loosely threaded along a path with guides in a loading position and thereafter the guides are repositioned to bring the label web to its operating position. In accordance with a specific embodiment of the invention, the label web passes from a roll and partially about first and second guides. Thereafter, the first and second guides are repositioned to bring the label web to an operating position. There is also a third guide and a back-up roll which are selectively operable between loading positions and operative positions. In the loading position the label web is passed partially around the third guide and a driven feed roll and in the operating position the label web passes partially around the guide and is in the nip between the feed roll and the back-up roll and is wrapped partially about the feed roll.
It is another feature of the invention to provide an improved ink jet printer which can print selectively either on one side or face of the label web or on both sides or faces of the label web in a single pass through the printer. According to the one specific embodiment, the label web can be threaded through the printer along either a first path for printing on one side of the label web or along a second path for printing on both sides of the web. The printer preferably has two print heads which are selectively movable between printing and non-printing positions with respect to the label web.
It is another feature of the invention to provide an ink jet printer for printing on both sides of a label web wherein one or more print modules are selectively removable from the printer. Each print module preferably includes all the structure for printing on the label web in response to data received. It is a simple matter to replace a print module having ink of one color with a like print module having ink of a different color. The removability of a print module also facilitates replacement of a malfunctioning print module, or removal of an unneeded print module while the remaining module is operational, or the servicing of the printer or its print modules.
It is also a feature of the invention to provide an ink jet printer for printing on both sides of a label web wherein one or more ink jet print heads are individually selectively positionable either in printing positions or in non-printing positions. A non-printing position is useful for example when threading the label web through the printer to prevent ink from the ink jet print head or heads from contacting the label web. The print heads can be moved to a non-operating or stored position whenever a the print head is not used. A wiper can wipe the print head clean of ink as the print head is being moved to its stored position and in the stored position a seal which seals off the orifices of the print head.
It is another feature of the invention to provide an improved printer having an ink jet print head connected to a source of ink by a pointed needle, wherein there is a guard for guarding off the pointed end of the needle. More particularly, the print head and the needle are part of a print head module which is removable from the printer, and the guard is effective until the print head module has been inserted into the printer. Upon insertion of the module into the printer the guard is deactivated.
It is another feature of the invention to provide an improved printer for printing on both sides of a label web, wherein an unwind mechanism helps to unwind a label web from a supply roll, to avoid excessive stretching of the label web wherein the label web can be threaded through the printer along one path in the event the label web is to be printed on both sides and along another path in the event the label web is to be printed on only one side, and wherein the label web is drawn through the printer by an advancing mechanism over either one of the paths.